"The vote demonstrates that West Bankers generally have a 'have to' relationship with the East Bank, and travel there mostly out of pure necessity."

We are a metropolis divided by a common river, on which we all depend. But not all of us depend equally on the other side of that river. The recent referendum to extend the toll on the Crescent City Connection, when mapped at the precinct level, sheds light on how we eye our cross-river compatriots, and how our residential positions influenced our vote.

As everyone now knows, supporters of keeping the bridge toll for another 20 years won the tri-parish referendum by an amazingly slim margin of 18 votes, 154,393 to 154,375. They had argued that the $1 fee (40 cents for those with toll tags) paid for critical maintenance on one of the busiest bridges in the nation, through a dedicated funding source underwritten by precisely those who crossed it. Opponents pointed to a state promise that the toll, which they felt impeded West Bank development and unfairly burdened its residents, would sunset once the bridge was paid off in 2012. They also cited past mishandling of toll revenue as evidence that it was time to remove this costly bottleneck.

How did we vote? When tabulated by bank, we see that those on the West opposed the toll by a commanding 60-40 margin, while voters on the East Bank supported it convincingly, 54-46. (These figures do not include early voters, whose precincts and banks could not be ascertained.) Had the vote been limited to West Bank residents, as many argued, the toll would have been soundly defeated: West Jeff, West Orleans, and West Plaquemines voters all opposed the tolls, by 61 percent, 53 percent and 56 percent respectively. Opponents also would have prevailed if the vote were limited to all of Jefferson (54 percent against) and/or Plaquemines (56 percent against), regardless of bank. What changed the calculus was the East Bank of Orleans, which voted 57 percent in favor.

Now a look at the deviations. A handful of West Bank precincts bucked the trend and supported the toll. Three were located in lower Plaquemines, home to folks so far from the metropolitan core that they use the bridge infrequently. The other West Bank supporters lived closest to the core, but they likely voted for different reasons. These were folks in Algiers Point, who depend heavily on the Algiers Ferry, a financially stretched operation that would breathe easier if the bridge tolls continued.

Fiercest opposition, meanwhile, came from precincts in Westwego, Marrero, and down the Barataria Boulevard corridor toward Lafitte, whose residents endure the longest commutes to East Bank destinations. There was also a fair amount of opposition, though not passionate, in the poorer pockets of New Orleans (including many housing projects) and in eastern Orleans Parish, including all areas east of Paris Road. Among them were voters in the predominantly Vietnamese-ancestry precincts of eastern New Orleans, whose residents have ties to brethren on the West Bank.

So, what have we learned about our metropolitan geography from this democratic exercise?

For one, the vote demonstrates that West Bankers generally have a "have to" relationship with the East Bank, and travel there mostly out of pure necessity, oftentimes daily. Those on the East Bank, on the other hand, are more likely go West for "want to" reasons, and/or only occasionally. So it makes perfect sense that the West Bank would seek to relieve itself of the daily toll burden while the East Bank is content to preserve the status quo. This asymmetrical cross-river relationship comes as no surprise, since the Central Business District, airport, and most people (nearly 70 percent), jobs, colleges, amenities and civic functions, not to mention ingresses and egresses to the rest of the nation, are positioned on the East Bank. The lopsided results also speak to the fiscal and physiological obstacle that West Bankers feel the toll imposes on economic and cultural activity radiating from the metropolitan core (which is unquestionably on the East Bank) to the periphery (which the West Bank constitutes).

We also learned something about folks in Orleans Parish, who largely drove the outcome of the referendum. Most New Orleanians satisfy most of their needs on the East Bank and have little need to cross the bridge, but this only partially explains their toll support. An inspection of the results shows that most of New Orleans' prosperous precincts, including Uptown, the Garden District, French Quarter, Marigny, Bywater and Mid City, voted strongly in favor of the toll, something that did not occur in East Jefferson, whose residents are also infrequent Crescent City Connection users.

What is probably going on here is that residents of the historic inner city, who tend to be progressive in their political philosophies, generally felt comfortable with a de facto usage tax for the bridge, while the more libertarian or conservative sensibilities of the East Jeff suburbs contested the notion that government should continue to collect fees for an asset already paid off. Whatever philosophical reasoning East Bankers might have brought to the polls, however, held little sway among the West Bankers who actually forked over the cash and endured the traffic jams. In essence, pocketbook pragmatism drove the West Bank vote, while the East Bank, unburdened by the daily nuisance and cost, indulged in a more philosophical rationale.

The returns also shed light on ferry supporters. Walking-distance proximity to the Algiers Ferry Landing was strongly correlated to toll support. The precinct closest to the ferry, in Algiers Point, supported the toll by a nearly 7-to-1 ratio, by far the highest anywhere much less on the West Bank. Those precincts located beyond five city blocks from the ferry supported the toll by 3-to-1 ratios, and the next tier outward by slight majorities -- after which ensued all-out opposition throughout most of the rest of the West Bank. Support could also be found near the East Bank ferry landing at the foot of Canal Street, but the numbers were indistinguishable from the rest of downtown support. We may surmise that West Bankers who use the ferry, while limited spatially and numerically, tend to be highly dependent on the service and passionately supportive of any policy that would keep it going.

Finally, it's worth noting that how we as Americans chose to resolve this matter is not the way many societies, including democracies, would have opted for. I was reminded of this a few days ago while conversing with a legislator of the National Assembly in France. After I explained to her the bridge controversy, she pointedly declared that such a matter should never have been put directly to citizens to decide because they would only vote in self-interest.

Perhaps, but in this case, self-interest mapped out to bank-wide interests, and I can think of no better way to give voice to those varied perspectives than by referendum. Decent folks and decent arguments, I believe, could be found on either bank of the river and on either side of this issue, and that's the real reason why the vote was so close.

Richard Campanella, a geographer with the Tulane School of Architecture, is the author of "Bienville's Dilemma," "Geographies of New Orleans" and other books. He may be reached at rcampane@tulane.edu; Twitter: @nolacampanella; richcampanella.com.